Miter-frame clamp



0. BERGSTROM. MITER FRAME CLAMP.

Patented June 8,1920.

2 SHFETYS SHEET l.

.Mhwfrf 1 gsro@ O BEHGSTROM,

MITER FRAME CLAMP. APPLucATxN FILED ocxla. 1919.

Patented J une 8, 1920.

2 SHEETS-SHEET 2.

g f .11| ,muah 46- gllllllllllllm UNITED .STATES PATENT OFFICE.

OSCAR BERGSTROM, OF CHICAGO, ILLINOIS, ASSIGNOR TO HANDY MANUFACTURING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATIONv 0F ILLINOIS. i

To all whom t may concern.'

Be it known that I, Oscar: Biancs'rnoar, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful j Improvement in Miter- Frame Clamps, of which the following is a specifi` cation. Y

This invention relates to machines for clamping together miter frames of wood and other material, especially the domes of phonograph cabinets while the parts are being glued or otherwise fastened together.

The object of the invention is to provide a small and therefore inexpensive machine adjustable to different sizes of frames or talking machine domes which can be easily and cheaply made, which is satisfactory in operation, and not readily liable to get out of order.

The invention consists in means for carrying out the foregoing objects, more particularly a machine in which carrying devices for clamping jaws for a talking machine dome or frame are readilyrmovable over the surface of aworking table without the use of guiding tracks or cuts therein and yet are provided with a very powerful compressing mechanism for forcing said clamping jaws against the corners of the dome or frame to be squared up and held in place. The invention further consists in many features and details of construction which will be hereafter more fully set forth in the specification and claims.

Referring to the drawings in which like numerals represent the same parts, throughout the several views,

Figure 1 is a plan view of a machine illustrating this invention in its preferred form.

Fig. 2 is a transverse sectional view on the line 2 2, Fig. 1.

Fig. 3 is a corresponding view parallel thereto on the line 3 3, Fig. 1.

Fig. 4 is a sectional detail view of certain parts taken on the line 4--4, Fig. 1.

In constructing the mechanism of this invention," a suitable table 10 is provided mounted on any suitable supporting legs which, in the particular case here illustrated, take the form of lugs 12. The upper surface of this table is provided with a plane true surface 14 with or without inter-V vening depressions 16, if desired, to reduce Specification of Letters Patent.

Patented June 8,1920.

Application filed October 15, 1919. Sera1 No. 330,884.

the amount of machine work on the top of the table. Extending across the table, in the particular case here illustrated in a recess 17 formed therefor is an operating screw 18 strapped into place by any suitable means as for instance the end blocks 20 and the lag screws 22. This screw 18 is held against endwise movement by any suitable means, as for instance a collar 24 on one end and a manually engageable hand wheel on the other end. Opposite end portions of the screw are provided with oppositely disposed screw threads 28 and 80, one set being right hand and the other left hand threads. Mounted on each half of the screw, one on each kind of screw threads, are two cross heads 32 and 34, normally placed about the same distance each side of the center of the screw 18. The result of this construction is that, as hand wheel 26 is rotated, thereby rotating the screw18, these crossheads 32 and 34 approach each other or move away from each other, depending upon the direction of rotation at the hand wheel and screw. As the securing devices 2() for the screw are at the sides of the table and the screw is operated from4 the side of the table the crossheads 83 and 34 can approach close together, thus permitting the machine to work on much smaller objects than with prior machines where the screw is equipped with center operating mechanism. On each opposite side of each cross head 82 and 34 is a pivot pin or bolt 36 and on each such pin or bolt .is journaled a yoke 38 clearly shown in Figs. 3 ,and 4 adapted to swing about its adjacent bolt 36 in a horizontal plane parallel to the surface 14 of the table. Rotatably mounted in each one of these yokes 38 is a screw 40 manually ro-V tatable by handle 42. Each screw 40 is threaded into a block 44. Depending from each block 44 is a member 48 more or less rigidly securing the base plate or block 46' thereto. Locating the adjusting screws 40 adjacent to the cross heads greatly simplifies the device both in construction and operation. This base plate rests on and freely swings about the adjacent bolt 36 in any position it may assume on the table, under the control of the adjacent cross head and screw 28. Each base plate 46 has pivoted to it on a screw 50 a clamping jaw block 52, clearly appearing in Fig. 2. Rising from this clamping jaw block 52 and secured thereto by screws 54 are two members 56 and 58 placed as shown in Fig. lat right angles to each other. When a frame having straight vertical sides is to be clamped, these members act as clamping jaws directly engaging the sides of the frame. However, in clamping talking machine domes it is necessary that pressure be applied yto the inclined corners at points intermediate of their vertical heights. Therefore, each one of these members 56 and 58 carries at a point substantially up from the block 52, a horizontal adjusting screw 60 equipped with a work engaging block 62 having `an inclined facie 63 designed to fit the surface of dome 72. These blocks and their supporting screw 62 are adjustable in and out under the control of lock nuts 64.

It will be noticed that all of the parts heretofore described are attached toa plane table by the securing devices 20 and that by removing these the entire loperating mechanism may be removed for repairs or to leave `the table free for other uses. Y On the'table adjacent to each base plate 46, is a guide member 66 which, in the particularrcase here illustrated, takes the form of a fork having in it a U-sharped slot 68 in whichis a bolt 70 inserted in a suitable holev in the table provided for it. By loosening the ybolt the adjusting fork may be adjusted bothlongitudinally and angularly to engage by contact only the side of the adjacent base plate.

In the operation of the device, the dome 72, shown in Fig. 2'to be worked upon, is placed over the approximate center of the table. The screws'70, and consequently the forks 66, are loosened or removed and the blocks 46 are swung freely on the pivots 36 provided for thel purpose in a horizontal plane over the table until the jaws 62 take bearing upon the respectivecorners ofthe dome. Each individual screw 40 is then adjusted until the parts controlled by it are in proper adjustment with reference to the dome, whereupon the operator can, by rotating wheel 26, move the cross heads 32 and 34 toward each other and thus force the members 62 into engagement with the dome corners, to square it and hold it together. In

i this position, the forks 66 are adjusted against the blocks 46, as shown. When the dome is finished, it is released by reverse movement of the hand wheel 26. The members 66 merely serve the function of guiding the blocks 46 during the releasing operation so that each engaging block 62 will move away about the same amount from its recently engaged corner of the dome 72.

Having thus described my invention what distance of the'work-engaging jaw device from its given cross head.

2. In mechanism ofthe class described, the combination of a working table, a pair of cross heads adjacent to the table, means for vvarying the distance between said cross heads, and a plurality of corner clamping devices attached to each cross headv and freely movable over the surface of the table,

a pivotal connection between `each cross head and each corner clamping mechanism whereby the clamping mechanismV may swing freely over the surface of the table, means immediatelyV adjacent to each cross head for adjusting the distance of each corner clamping device to its adjacent cross head. Y

3. In mechanism of the class described, the combination of a plane surface working table, a recess extending across the table in which a screw is adapted to lie, a screw in said recess, straps 2O at each end of theV screw securing it rotatably on the table, oppositely inclined screw threads on opposite end portions of the screw, a cross headV on each side of the center of the'table one en- ,gag-ing each kind of screw threads on the screw, means beyond the table edge for rotating said screw, a plurality of work clamping jaw mechanisms bearing on said table in frictional engagement onlyv therewith, arranged in two groups oneattached to each crosshead, wherebyon rotating said screw the respective groups ofV clamping mechanisms are drawn together and'on rc- D. B. CHEEvEn, i Y Y Y ANNA RosnN'rI-IAL.V g 

